Air-pump.



C. W. MANZEL.

Patented Jan. 23,1917.

INVEUR b1 7M M ATTURNEY.

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CHARLES W. MANZEL, 0F BUFFALO, NEW YORK, AISSIGNOR T0 MANZEL BROTHERS COMPANY, OF BUFFALO, NEW YORK, A CORLORATION OF N EW YORK.

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Specification of Letters Patent.

Patented dan. 23, 191V?.

To aZZ whom zt may concern:

Be it known that I, CHARLES W. MANZEL, a citizen of the United States, residing at Bui-falo, in the county of Erie and State of New York, have invented new and usefull `Improvements in Air-Pumps, of which the deliver the air 'entirely free from oil, this being necessary in order to preserve the life of the tire.

Further objects of the invention are to simplify the construction of the pump, render it light and compact, reduce its cost of manufacture and facilitate the assemblage of its parts.

In the accompanying drawings: Figure 1 is. a vertical section of my improved pump. Fig. 2 is a horizontal section of the same on line 2 2, Fig. 1. Fig 3 is-a transverse vertical section of the safety valve on line 3 3, Fig. 1. v

Similar-characters of reference indicate corresponding parts throughout the several views.

ln the drawings, the invention is illustrated as applied to a duplex pump.

l indicates the cylinders or barrels of the pump,preferably provided at their lower ends w1th a Hange 2 which is screwed or otherwise secured to the top of the crank case 3. One head of this case may be cast integral therewith, while its opposite end is closed by a removable cap t suitably cured thereto. n y

5 indicates the plungers or pistons arranged in the cylinders 1 and adapted to be reciprocated therein by a rotatable crank shaft 6 journaled in the ends of the crank case 3, the pistons being connected with the cranks 7 of said shaft by connecting rods 8 and the crank case havingvan opening in its top for the passage of said rods andthe pistons. Said case is designed to containa suitable quantity of oil for lubricating the shaft bearings and the pump pistons, in a well known manner.

9 indicates a plurality of air inlet ports or openings leading into the pump cylinders 1 and preferably arranged radially around the circumference thereof, as shown. These ports are located so as to be uncovered by the pistons when the latter are in their ,lowermost or rearmost position, thereby admitting a charge of air to the cylinders in front of the pistons.

Arranged in the inner side of each pumpcylinder is an annular groove 10 which preferably intersects or communicates with all of the air inlet ports 9, to form a continuous air passage around the interior of the cylinder. As is well known, the pistons upon their return stroke produce a partial vacuum in the upper part of the cylinders which ordinarily has a. tendency to draw oil from the lower portion of the cylinder and past the pistons into the upper portion of the cylinders, whence it is discharged with the air. This is obviously objectionable when the pump is used for inflating automobile tires, because of the disintegrating effect of the oil which shortens the life of the tire. By providing each pump cylinder with an annular groove 10 in communication with the outer atmosphere, said partial vacuum is broken not only in longitudinal lines passing through the inlet openingsI 9, but entirely around the' cylinder, thus practically preventing oil` from being drawn above the pistons', delivering the air free from oilv into the tires and avoiding deterioration of the latter.

As shown inthe drawings,`the discharge port or passage 11 of each pump cylinder is preferably arrangedcentrally in its head, and the head or front end ofeach piston is convex, as shown at 12. By this construc- Ltio'n and arrangement any slight quantity of oilthat may leak past the plston 1s driven toward a-nd. against the wall of the cylinder where it is least liable to commingle with the air which is expelled through the central portion of the cylinder head. The heads of the cylinder are provided with concave reycesses 13 which receive the' convex heads of the pistons.

14 indicates outlet chambers respectively connected with the pump cylinders by the discharge ports 11 and both'connected with a common outlet 15. by passages 16. To this outlet is attached the customary hose 17 4which connects the pumpwith the tire -or other air.

18 indicates spring-pressed or other suitpart to be supplied with compressed able check valves controlling the discharge ports 11.

Centrally located between and commonto both outlet chambers 14 is a safety or pressure-relief valve 19 which is normally held closed by a spiral spring 20 which is compressed to the desired tension by an adjusting screw 21. The latter is protected by a screw cap 22 engaging the upper end lof the case 23 containing said safety valve. This case has a discharge passage 24 for the escape of the excess air pressure. In inflating atire, the safety valve is set at the r'equired pressure, and when thisA is,reached any excess pressure opens the safety valve and passes outl through the discharge .passage 24 in an obvious manner. For simplicity, compactness and cheapness of construction, the outlet or valve chambers `14 arepreferably cast integrally with'thel pump cylinders, as shown. The pump may be thrown into and -out of gear with suitable driving mechanism by any suitable means. That shown in the drawings comprises a gear 25 splined on the crank shaft 6 and adapted to be shifted into or out of gear with a driving gear, not shown, by means of a hand lever .26. It will be noted 'that the outlet chambers 14 and the safety valve 19 are so arranged with relation to each other that temporary disability of either piston does not affect the working of the other.

The peculiar,construction and arrangement of the pump cylinders and the crank case permits convenient assemblage of the parts, as well as their readydismemberment for inspection and repairs. It also` permits renewal of the cylinders when worn out, without the necessity of renewing also the misma 'base or crank case. As shown in the drawings, the heads of the pump cylinders are solid or integral with the cylinder-bodies. By this' construction leakage at the upper ends of the cylinders is avoided and no packing is required. n

In assembling the parts, the crank shaft is first put in place in the crank case after which the cap 4 of the latter is a plied; the connecting rods 8 are then attac ed to the crank shaft and thepistons pinned to the rods, and finally the cylinders are slipped over the pistons and fastened to the crank case.

I claim as my invention:

ln an air pump, the `combination of a ycrank case, a crank-shaft journaled therein,

a pair of integral' pump-cylinders seated side by side on the crank case and removably secured thereto, said cylinders being closed at their upper ends by integral heads and their lower ends opening into the crank case, a piston in each cylinder connected with the crank shaft, each cylinder having in its head an outlet chamber containing a check-valve, said valves being located at the same'ends of the cylinders, a discharge conduit connected with both of said outlet chambers, a valve chamber located between said outletchambers and communicating with both of the same, and a safety-valve located in said valve chamber.

9`Witness my hand this 26th day of August, 1 12.

CHARLES w. NZEL.

v`Witnessesz C. F. Glam, E. M. GRAHAM. 

